The U.S. Pat. No. 4,805,648 titled "Automatic washing and sterilizing device for a stable" has a structure wherein two cranes provided with a spraying system are to be moved by ropes pulled and wound by wind drive wheels driven by a speed transmission system connected with motors. The nozzles are connected with pipes and valves to shoot or spray water or sterilizing solution selectively. The moving direction of the cranes is altered by two location switches having a control bar to be touched by the plates of the cranes. The structure is rather complicated, and besides, the spraying angle and scope is limited, and unable to freely adjust because of the nozzles 34 are controlled by a synchronous motor 27.